US1968609A

US1968609A - Lawn mower sharpening means

Info

Publication number: US1968609A
Application number: US607567A
Authority: US
Inventors: Carl J Madsen
Original assignee: DANIEL M ALRED
Current assignee: DANIEL M ALRED
Priority date: 1932-04-26
Filing date: 1932-04-26
Publication date: 1934-07-31
Anticipated expiration: 1951-07-31

Description

July 31, 1934. c. J. MADSEN LAWN MOWER SHARPENING MEANS Filed April 26, 1932 3 Sheets-Sheet l Inventor, Ca rl JMada e/L, 13V

July 31, 1934. c:. .LMADSEN LAWN MOWER SHARPEIIQING MEANS Filed April 26, 1932 3 Sheets-Sheet 2 Y [nven for, Carl J Madaeru @m'mm 41 for/ aya- July 31, 1934. Q J A N I 1,968,609

LAWN MOWER SHARPENING MEANS Filed April 26, 1932 3 Sheets-Sheet 5 [n vemon Car/ 1. Madman,

Patented July 31, 1934 UNITED STATES LAWVN MOWER SHARPENING MEANS Carl J. Madsen, Indianapolis, Ind, assignor of one-half to Daniel M. Aired,

Ind.

Application April 26, 1932,

11 Claims.

This invention relates to the art of grinding machines and particularly to a mechanism to be employed to sharpen the cutting edges of the stationary and rotary knives of a lawn mower. One of the primary objects of the invention is to provide a grindingdevice which may be readily adjusted to various sizes and types of lawn mowers whereby in each case the rotary and stationary knives may be ground to give the delo sired clearance for proper cutting.

A further primary object of the invention is to provide in combination with a grinding wheel locating and guide means such that the knives w on'the rotary wheel may be ground to follow variations existing along the cutting edge of the stationary knife. A still further important object of the invention is to provide-gauge means in combination with the grinding wheel whereby the wheel may be guided longitudinally of the cutting edge of the knife of the reel so as to maintain a constant cutting angle therealong.

These and other objects and advantages such as arise from the particular combination of elements employed will become apparent in the fol- 5 lowing description of the invention as illustrated in one particular form in the accompanying drawings, in which i Fig. l is afragmentary front elevation of an assemblyembodying my invention;

Fig. 2, a vertical transverse section on the. line 22 in'Fig. 1; showing the grinding wheel positioned after starting but before the completion of thegrinding of a hollow in the blade; to the cutting edge of the blade;

post: attaching means; i

Fig. 4, a transverse horizontal section on the line 4-4 in Fig. 3 on an enlarged scale;

Fig. 5, a detail in bottom plan View of the knife edgegauges;

Fig. 6, a rear elevation of the driving motor and base;

'7, a fragmentary top plan view, of the grinding head as employed in cutting the station- 5 ary knife; 1 r Fig. 8, a transverse vertical section through the stationary knife and the supporting base showing the grinding head applied thereto in the position for cutting the knife edge;

Fig. 9, a topplanview' of the base :with mower supporting brackets carried thereby, and

' Fig. 10', a vertical transverse section through a lawn mower with the grinding head applied thereto asemployed for-grinding the cutting eeedgeszofsthe reeluknives,

Fig. 3, a detail in rear elevation of the guide;

Indianapolis,

Serial No. 607,567

Like characters of reference indicate :like parts throughoutthe several views in the drawings.

In employingmy invention,'the first operation is to remove the stationary knife 15 from the mower. The means of holding this knife 15in place in the mower varies with the individual construction thereof as employed by various manufacturers. In some cases this knife is riveted to or is even an integral part of. a transverse bar extending across the mower below the reel.- In other cases the knife is detachably mounted on a bar 16 as here shown, Fig. 10, by screws so that the knife may be removed from the bar 16 without having to, disturb other parts. Regardless of how the knife 15 may be held, it is taken from the mower either with its supporting bar or removed therefrom when possible as herein shown and is mounted on the top side of-a bed 1'7 and secured thereon by means of the

clamping plates

18 and 19 to be right side up and to have the forward edge preferably extending forwardly of the bench, Fig. '7. These

plates

18 and 19 have thumb screws 20 and 21 respectively slidably passed therethrough and screw-threadedly engaged in transverse bars 22' therebelow to fit between the vertically disposed channel bars 23'and 24 i (Fig. 2) which are fixed between the

brackets

25 and 26 to form the bed 17. These

plates

18 and 19 are so formed that they may be clamped down on the top-side of the fiat knife 15 to;hold it rigidly in place or they maybe turned around to have the pointedends thereof engage over or through end-holes (not shown). of the knife retaining bar where the knife is not removed from that bar.

I employ a motordrive unit, Figs. 1 and 6, wherein a motor 27 is mounted on a platform 28 which inturn is swivelly mounted on a base 29. This base 29 is provided with two

fixed legs

30 and 31 and a 'rockableleg 32 such that by rocking the leg 32 around and upwardly the base 29 may be lowered on the one side to have the other side held. in the elevated position by the two

legs

30, 31. The leg 32 is rocked around to drop into a slot appearing in the edge of the platform28 soas to retain the platform in a fixed position against rotation. The. drive shaftbfthe motor 27 is: provided with a stepped pulley B3 and a post .34. is carried by the platform 28'to extend upwardly, and carried toward its upper end is a transverse shaft-35 on which is mounted a stepped or-conepulley 36. A drive belt 37 passes around the two pulleys-as a means of drivingthe shaft 35 from the motor 27. A-fiexible shaft is-carried from the end of the shaft35 through amuse-.

ing 38 in the usual manner and has a grinding wheel 39 connected thereto at its outer end.

A guide handle is provided to support the outer end of the flexible shaft and a wheel guard 41 is fixed thereto to substantially enclose the major portion of the side of the wheel toward the handle and also of the periphery. The base 29 is turned in relation to the bed 17 to have the

legs

30, 31 toward the bench and the leg 32 on the side of the base away from the bench and rocked upwardly whereby the post 34 is normally positioned to slope away from the end of the bed. Now by carrying the wheel 39 longitudinally along the bed 1'7 by means of the handle 40, the wheel may be carried to the left to rock the post 34 around toward the bed and as the wheel is carried to the right again, the weight of the motor unit will tend to pull the wheel along by reason of that weight having been fulcruined about the

legs

30 and 31.

The guard 41 is cut away from the lower side and on the lower front face thereof is mounted a knife edge gauge. This gauge comprises a bracket 42 secured to the guard by means of the screws 43, 44 which slidably pass through the bracket 42 and screw-threadedly engage the guard. These screws 43, 44 are located transversely across the bracket in relation to each other and are toward the lower end of the bracket. An adjusting screw 45 screw-threadedly passes through the outer or upper end of the bracket 42 to have its end abut the guard. Thus by running the screw 45 in or out through the bracket,

v the bracket may be rocked in relation to the guard. The bracket is provided with a boss 46 through which a thumb screw 47 screwthreadedly passes to beneath the wheel 39. By rocking the bracket 42 by means of the screw 45, the

. end of the screw extending to under the wheel i may be shifted toward or away from the periphcry of the wheel as required. A wing nut 48 is carried on the screw 47 as a means of locking the screw 47 at desired points of adjustment. A roller 49 having a V-shaped groove therearound is rotatably mounted on the under side of the brack- On the back side of the guard 41 is carried a guide post 50, longitudinally slidable through a block 51. This block 51 is rockably carried be- 1 tween the

cars

52 and 53 extending rearwardly from the guard 41 so that the block 51 may swing in a plane parallel to the plane of rotation of the wheel 39. A spring pressed plunger 54 is carried by the block 51 to extend therefrom below the

ears

52, 53 to yieldingly bear against the guard 41 so that the block 51 is normally rocked thereby to throw the upper end around toward the housing or guard 41. The post a may be adjusted longitudinally through the block 51 and secured in selected positions by means of the thumb screw 55 which screw-threadedly passes through the block 51 to carry a disk 56 against a flat side of the post 50. A spring 5'1 v presses the disk 56 into frictional engagement with the post 50 so that although the screw 55 may be withdrawn the post 50 will yieldingly remain at any position. The lower end of the post 50 is cut off to receive thereagainst the end of a roller 58 whose axis is at an angle with that of the post 50.

Referring now to Figs. 1, 2 and '7, the wheel 39 is brought down against the upper side of the knife 15 and the screw 47 is adjusted to bear against the forward edge of the knife and the post 50 is also adjusted vertically through theblock 51 and also in a rocked position by means of a screw 59 which passes through the guard 41 from the forward side between the wheel 39 and the guard and back through the rear side of the guard to abut the block 51 above the

cars

52, 53. Both the

screws

47 and 59 are suitably adjusted to bring the grinding wheel 39 to that position over the knife 15 as indicated in 2 which will cause the wheel to cut away the shoulder A which is left at the upper end of that face of the knife 15 against which the knives of the reel have been in contact. The correct position of the wheel 39 as just indicated is maintained by allowing the rear end of the screw 47 to bear against the front edge of the knife 15 and to have the roller 58 bear downwardly against the angle-bar 60 which extends along the rear side of the bed 17. Now by shifting the wheel 39 longitudinally along the knife 15 by means of the handle 40, the shoulder A may be cut away to give the desired clearance. The motor 27 is preferably controlled by means of a switch 61 mounted conveniently on the top side of the handle 40.

Following the initial cutting action of cutting away the shoulder A for clearance on the top side of the knife 15 as above indicated, the knife 15 is removed from under the

plates

18 and 19 and is set on edge as indicated in Fig. 8, to have the.

cutting edge of the knife turned upwardly and forwardly. A suitable clamp screw 62 is screwthreadedly passed through the front channel bar 24 to bear against the lower or rear part of the knife 15 to rock it back against a block 63 so that the knife 15 does not rest vertically but is inclined forwardly somewhat. The grinding wheel 39 is then brought over the top edge of the knife thus positioned and the screw 47 is brought against the then forward side of the knife while the screw 59 is also adjusted to rock the post 50 as its lower end bears or rests on the angle bar 60 so that the edge of the knife 15 may be ground off to form an angle slightly less than 90 degrees with the face being contacted by the screw 47 and to form a sharp corner thereby. The wheel 39 is shifted longitudinally along this edge of the knife 15 to complete the grinding thereon, following which grinding the knife 15 is then returned to its normal position in the mower as indicated in Fig. 10. The knives 64 of the reel 65 are then to be sharpened.

In order to place the mower in a suitable position and to there support it, I provide the brackets 66 and 67 which are clamped down by the

plates

18 and 19 on the bed 17 to extend forwardly therefrom and the upper sides of-these brackets are provided with the notches across which the tie bar 68 of the mower may rest to support the mower in an inverted position with the handle 69 thereof extending downwardly against any suit able support here shown as the edge of the table 70. The handle 69 may of course be removed but this is not necessary and the exact position of the mower as supported in relation to the bed 17 makes no diiference insofar as the cutting action is concerned since the position is merely determined for the convenience of the operator.

Now to sharpen a knife blade 64 of the reel, I bring the grinding wheel 39 to over that particular blade and also revolve the reel so that the roller 49 is brought against the cutting edge of the knife 15, the back end of the screw 4'7 against the blade 64 and the roller 58 against the next adjacent blade 64'. Now by shifting the wheel 39 longitudinally the roller 49 bearing against the edge of the knife 15 will maintain the wheel r39. in parallel alignment therewith: and the conotacting of. the screw 47. withsthe one .blade being ground and theroller. 58 with the next adjacent blade will also. maintain the wheel-.391 at they re- .quired position tojgive the. desired cutting angle -s donv the edgeiofi'itheknife. zMoreovcnsince the screw .47 bears against the-.sidezof the knife, the ,7

reel will be revolved .as thewheel 39 is shifted 1 along=the knife. Inorderuto maintainthe knife "64: securely againstlthe screw 47 Iaprovidea spring appearingdnthe. knife 15. Alsoattention. is di- -rected-tothe fact-that the roller158 bears against ithe edge of thenextblade-BQ in such a manner that theirockinglof Jthewheel .39 around over the edge of the blade 64 is limited thereby so that the amount as well as the angle of grinding along the edge of the blade 64 is adjustably controlled.

While I have here shown and described my invention in the form as now best known to me, it is obvious that structural changes may be made therein without departing from the spirit of the invention and I, therefore, do not desire to be limited to that precise form beyond the limitations as may be required by the following claims.

I claim:

1. In a sharpening device for lawn mowers having a stationary blade and a reel blade, a grinding unit adapted to be moved parallel with the stationary blade and guided solely by contact with the stationary blade and reelblade, said unit comprising a grinding wheel, a post rockably mounted back of the wheel to be shiftable parallel to the plane of rotation of the wheel and to bear against a guiding member of the mower, a stop adjustably located below the wheel to engage and guide the reel blade being ground, and means carrying said post and said stop fixed Stationary in respect to rotation of the wheel but fixed to be shiftable therewith.

2. In a sharpening device for lawn mowers having a stationary blade and a reel blade, a grinding unit adapted to be moved parallel with the stationary blade and guided solely by contact with the stationary blade and reel blade, said unit comprising a grinding wheel, a post rockably mounted back of the wheel to be shiftable parallel to the plane of rotation of the wheel and to bear against a guiding member of the mower, a stop adjustably located below the wheel to engage and guide the reel blade being ground, and

means carrying said post and said stop fixed stationary in respect to rotation of the wheel but fixed to be shiftable therewith, and a roller revolubly carried forward of said stop.

3. In a sharpening device for lawn mowers having a stationary blade and a reel blade, a grinding unit adapted to be moved parallel with the stationary blade and guided solely by contact with the stationary blade and reel blade, said unit comprising a grinding wheel, a post rockably mounted back of the wheel to be shiftable parallel to the plane of rotation of the wheel and to bear against the tangential face of a reel blade, a stop adjustably located below the wheel to engage and guide the reel blade being ground, and means carrying. said post and said stop I fixedlstationary in respect to rotation of the wheel but fixed to be shiftable therewith, saidstop comprisinga "member adapted to be extended to and retracted .fromnnder the. periphery Ofllih. wheel; =1

4..In a sharpening :device "for lawn...mowers having stationary and rockablel blades, a #power driven. grinding unit adapted to be; guidedisolely by contact. with; thewstationary. and revolving blades of the mowing machine comprising ashift- (12 able grinding wheel, a .post rockably mounted back of the wheel to be shiftable parallel-tothe planeof rotation of the wheel, astop adjustably located-below the wheel, and meanscarrying said .post. andsaid stopfixedstationary in respecttotiiQO rotation of theswheel but fixed tozbe shiftable therewith, saidi-stop comprising a member adapted to be extended to and retracted from under the periphery of the wheeLand abracket carrying the stop adaptedto'be locked to varythe anglegsiQS of the member with the wheel.

5. In a grinding device for lawn mowers having stationary and rotary reel knives, a shiftable power driven unit movable parallel withthe stationary knife and guided in such;movemente and1at a definite angular relation thereto solely by guides bearing upon the reel and stationary knives of the machine, said unit comprising a grinding wheel, a guard about the wheel, a post rockably supported from the rear of the guard, a reel knife stop carried toward the lower end of the forward side of the guard, a stationary knife roller spaced forwardly of the stop on the guard, and means for adjusting the angularity of said post in respect to said wheel, said stop being adapted to bear against the reel knife being ground with said roller in contact with the stationary knife, and said post being adjusted to bear against the next adjacent knife on the reel.

6. In a grinding device for lawn mowers having-.1 15 stationary and rotary reel knives, a shiftable power driven unit movable parallel with the stationary knife and guided in such movement and at a definite angular relation thereto solely by guides bearing upon the reel and stationary knives of 51:20

the machine, said unit comprising a grinding wheel, a guard about the wheel, a post rockably supported from the rear of the guard, a reel knife stop carried toward the lower end of the forward side of the guard, a stationary knife roller spaced forwardly of the stop on the guard, and means for adjusting the angularity of said post in respect to said wheel, said stop being adapted to bear against the reel knife being ground with said roller in contact with the stationary knife,;:1s30 and said post being adjusted to bear against the next adjacent knife on the reel, a motor drive unit, a base supporting the unit having a pair of legs over which said unit may be fulcrumed, and a flexible shaft drive from the unit to said ;1,35 wheel, said unit being so located that as the wheel is advanced along the mower knife, said unit is rocked over said legs.

'7. In a grinding device for lawn mowers having a knife and a knife holding bed, a manually shift-2,140 able power driven grinding unit for use with the bed for holding the stationary knife of the mower, said unit guided solely by contact against the face of the knife and face of the bed, said unit and said bed comprising a grinding wheel adapted to bep shifted longitudinally of the bed, a guard about the wheel, a post mounted on the guard to extend down therebehind, and be rockable toward and away from the wheel, means for limiting the rearward rotation of the lower end of the post,1;

8. In a grinding device for lawn mowers having a stationary knife and a reel knife, arotatable grinding unit adapted to be moved parallel with the stationary knife and guided solely by guides bearing upon the stationary knife and a knife of the reel, a grinding wheel, a guard about the wheel, a post rockably supported from the rear of the guard, a reel knife stop carried toward the lower end of the forward side of the guard, a stationary knife roller spaced forwardly of the stop on the guard, and means for adjusting the angularity of said post in respect to said wheel, said stop being adapted to bear against the reel knife being ground with said roller in contact with the stationary knife, and said post being adjusted to bear against the next adjacent knife on the reel, and means yieldingly holding said reel knife against said stop.

9. In a sharpening device for lawn mowers having a stationary blade and a revolving blade, a shiftable grinding unit adapted to be guided solely by the stationary and revolving blades of the mower, said unit comprising a grinding wheel with means for rotating it, and adjustable guide means for engaging the stationary blade, the blade of the reel being ground and the adjacent reel blade.

10. In a sharpening device for lawn mowers having a stationary blade, a frame to which the" stationary blade is clamped, a face on the frame parallel with the blade and unobstructed by the blade, and a power driven rotatable grinding wheel unit adapted for movement along the blade and guided solely by guides'on the unit engaging I? the blade and the face on the frame while the blade is clamped on the frame.

11. In a sharpening device for lawn mowers having a stationary blade, a frame to which the stationary blade is clamped, a face on the frame CARL J. MADSEN.